Question

Latha bought a pencil and a pen for seven and a half rupees. She gave Rs 10/-. The shopkeeper gave back the money in half and quarter rupees. What is the minimum number of coins she got?

Answer 1

Hint: To solve this problem you should know basic arithmetic knowledge and basic logical ability. In this type of questions you should divide the returnable amount by big coin then we obtain the number of big coins as quotient and remaining amount as remainder. Then divide remainder by small coin, obtain quotient will be number of small coin and remainder will be remaining amount. Continue this process until you get zero as remainder.

Complete step-by-step answer:
It is said that Latha has bought a pencil and a pen for $Rs.7.5$ and gave $Rs.10$ to the shopkeeper.
So the money return by shopkeeper $ = Rs.10 - Rs.7.5 = Rs.2.5$
The shopkeeper returned Rs.2.5 to Latha.
So, if he had to return it in a minimum number of coins.
Highest value coin is RS. 0.5. so, if return her Rs. 0.5 coin,
The number of coin he return \[ = \dfrac{{2.5}}{{0.5}} = 5\]
The shopkeeper can return coins in multiple ways but for the minimum number of coins he must return 5 half rupee coins.
Hence, the minimum number of coins is 5.

Note: Here we have to find the minimum number of coins if it has been changed and you have to find the maximum number of coins required to pay her back. Then we start with a small value coin then we go for a bigger one to complete its sum. Always keep in mind the nature of our question and solve it.